Abstract. Refractive and absorption indices in the UV and visible region of selected
aqueous organic acids relevant to tropospheric aerosols are reported. The
acids investigated are the aliphatic dicarboxylic acids oxalic, malonic,
tartronic, succinic and glutaric acid. In addition we report data for
pyruvic, pinonic, benzoic and phthalic acid. To cover a wide range of
conditions we have investigated the aqueous organic acids at different
concentrations spanning from highly diluted samples to concentrations close
to saturation. The density of the investigated samples is reported and a
parameterisation of the absorption and refractive index that allows the
calculation of the optical constants of mixed aqueous organic acids at
different concentrations is presented. The single scattering albedo is
calculated for two size distributions using measured and a synthetic set of
optical constants. The results show that tropospheric aerosols consisting of
only these organic acids and water have a pure scattering effect.